2 * Copyright (C)2002 USAGI/WIDE Project
4 * This program is free software; you can redistribute it and/or modify
5 * it under the terms of the GNU General Public License as published by
6 * the Free Software Foundation; either version 2 of the License, or
7 * (at your option) any later version.
9 * This program is distributed in the hope that it will be useful,
10 * but WITHOUT ANY WARRANTY; without even the implied warranty of
11 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
12 * GNU General Public License for more details.
14 * You should have received a copy of the GNU General Public License
15 * along with this program; if not, write to the Free Software
16 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
20 * Mitsuru KANDA @USAGI : IPv6 Support
21 * Kazunori MIYAZAWA @USAGI :
22 * Kunihiro Ishiguro <kunihiro@ipinfusion.com>
24 * This file is derived from net/ipv4/ah.c.
27 #define pr_fmt(fmt) "IPv6: " fmt
29 #include <crypto/hash.h>
30 #include <linux/module.h>
31 #include <linux/slab.h>
34 #include <linux/crypto.h>
35 #include <linux/pfkeyv2.h>
36 #include <linux/string.h>
37 #include <linux/scatterlist.h>
38 #include <net/ip6_route.h>
41 #include <net/protocol.h>
44 #define IPV6HDR_BASELEN 8
47 #if defined(CONFIG_IPV6_MIP6) || defined(CONFIG_IPV6_MIP6_MODULE)
48 struct in6_addr saddr;
50 struct in6_addr daddr;
55 struct xfrm_skb_cb xfrm;
59 #define AH_SKB_CB(__skb) ((struct ah_skb_cb *)&((__skb)->cb[0]))
61 static void *ah_alloc_tmp(struct crypto_ahash *ahash, int nfrags,
66 len = size + crypto_ahash_digestsize(ahash) +
67 (crypto_ahash_alignmask(ahash) &
68 ~(crypto_tfm_ctx_alignment() - 1));
70 len = ALIGN(len, crypto_tfm_ctx_alignment());
72 len += sizeof(struct ahash_request) + crypto_ahash_reqsize(ahash);
73 len = ALIGN(len, __alignof__(struct scatterlist));
75 len += sizeof(struct scatterlist) * nfrags;
77 return kmalloc(len, GFP_ATOMIC);
80 static inline struct tmp_ext *ah_tmp_ext(void *base)
82 return base + IPV6HDR_BASELEN;
85 static inline u8 *ah_tmp_auth(u8 *tmp, unsigned int offset)
90 static inline u8 *ah_tmp_icv(struct crypto_ahash *ahash, void *tmp,
93 return PTR_ALIGN((u8 *)tmp + offset, crypto_ahash_alignmask(ahash) + 1);
96 static inline struct ahash_request *ah_tmp_req(struct crypto_ahash *ahash,
99 struct ahash_request *req;
101 req = (void *)PTR_ALIGN(icv + crypto_ahash_digestsize(ahash),
102 crypto_tfm_ctx_alignment());
104 ahash_request_set_tfm(req, ahash);
109 static inline struct scatterlist *ah_req_sg(struct crypto_ahash *ahash,
110 struct ahash_request *req)
112 return (void *)ALIGN((unsigned long)(req + 1) +
113 crypto_ahash_reqsize(ahash),
114 __alignof__(struct scatterlist));
117 static bool zero_out_mutable_opts(struct ipv6_opt_hdr *opthdr)
119 u8 *opt = (u8 *)opthdr;
120 int len = ipv6_optlen(opthdr);
137 optlen = opt[off+1]+2;
141 memset(&opt[off+2], 0, opt[off+1]);
155 #if defined(CONFIG_IPV6_MIP6) || defined(CONFIG_IPV6_MIP6_MODULE)
157 * ipv6_rearrange_destopt - rearrange IPv6 destination options header
159 * @destopt: destionation options header
161 static void ipv6_rearrange_destopt(struct ipv6hdr *iph, struct ipv6_opt_hdr *destopt)
163 u8 *opt = (u8 *)destopt;
164 int len = ipv6_optlen(destopt);
181 optlen = opt[off+1]+2;
185 /* Rearrange the source address in @iph and the
186 * addresses in home address option for final source.
187 * See 11.3.2 of RFC 3775 for details.
189 if (opt[off] == IPV6_TLV_HAO) {
190 struct in6_addr final_addr;
191 struct ipv6_destopt_hao *hao;
193 hao = (struct ipv6_destopt_hao *)&opt[off];
194 if (hao->length != sizeof(hao->addr)) {
195 net_warn_ratelimited("destopt hao: invalid header length: %u\n",
199 final_addr = hao->addr;
200 hao->addr = iph->saddr;
201 iph->saddr = final_addr;
209 /* Note: ok if len == 0 */
214 static void ipv6_rearrange_destopt(struct ipv6hdr *iph, struct ipv6_opt_hdr *destopt) {}
218 * ipv6_rearrange_rthdr - rearrange IPv6 routing header
220 * @rthdr: routing header
222 * Rearrange the destination address in @iph and the addresses in @rthdr
223 * so that they appear in the order they will at the final destination.
224 * See Appendix A2 of RFC 2402 for details.
226 static void ipv6_rearrange_rthdr(struct ipv6hdr *iph, struct ipv6_rt_hdr *rthdr)
228 int segments, segments_left;
229 struct in6_addr *addrs;
230 struct in6_addr final_addr;
232 segments_left = rthdr->segments_left;
233 if (segments_left == 0)
235 rthdr->segments_left = 0;
237 /* The value of rthdr->hdrlen has been verified either by the system
238 * call if it is locally generated, or by ipv6_rthdr_rcv() for incoming
239 * packets. So we can assume that it is even and that segments is
240 * greater than or equal to segments_left.
242 * For the same reason we can assume that this option is of type 0.
244 segments = rthdr->hdrlen >> 1;
246 addrs = ((struct rt0_hdr *)rthdr)->addr;
247 final_addr = addrs[segments - 1];
249 addrs += segments - segments_left;
250 memmove(addrs + 1, addrs, (segments_left - 1) * sizeof(*addrs));
252 addrs[0] = iph->daddr;
253 iph->daddr = final_addr;
256 static int ipv6_clear_mutable_options(struct ipv6hdr *iph, int len, int dir)
260 struct ipv6_opt_hdr *opth;
261 struct ipv6_rt_hdr *rth;
263 } exthdr = { .iph = iph };
264 char *end = exthdr.raw + len;
265 int nexthdr = iph->nexthdr;
269 while (exthdr.raw < end) {
272 if (dir == XFRM_POLICY_OUT)
273 ipv6_rearrange_destopt(iph, exthdr.opth);
275 if (!zero_out_mutable_opts(exthdr.opth)) {
277 KERN_WARNING "overrun %sopts\n",
278 nexthdr == NEXTHDR_HOP ?
284 case NEXTHDR_ROUTING:
285 ipv6_rearrange_rthdr(iph, exthdr.rth);
292 nexthdr = exthdr.opth->nexthdr;
293 exthdr.raw += ipv6_optlen(exthdr.opth);
299 static void ah6_output_done(struct crypto_async_request *base, int err)
304 struct sk_buff *skb = base->data;
305 struct xfrm_state *x = skb_dst(skb)->xfrm;
306 struct ah_data *ahp = x->data;
307 struct ipv6hdr *top_iph = ipv6_hdr(skb);
308 struct ip_auth_hdr *ah = ip_auth_hdr(skb);
309 struct tmp_ext *iph_ext;
311 extlen = skb_network_header_len(skb) - sizeof(struct ipv6hdr);
313 extlen += sizeof(*iph_ext);
315 iph_base = AH_SKB_CB(skb)->tmp;
316 iph_ext = ah_tmp_ext(iph_base);
317 icv = ah_tmp_icv(ahp->ahash, iph_ext, extlen);
319 memcpy(ah->auth_data, icv, ahp->icv_trunc_len);
320 memcpy(top_iph, iph_base, IPV6HDR_BASELEN);
323 #if defined(CONFIG_IPV6_MIP6) || defined(CONFIG_IPV6_MIP6_MODULE)
324 memcpy(&top_iph->saddr, iph_ext, extlen);
326 memcpy(&top_iph->daddr, iph_ext, extlen);
330 kfree(AH_SKB_CB(skb)->tmp);
331 xfrm_output_resume(skb, err);
334 static int ah6_output(struct xfrm_state *x, struct sk_buff *skb)
342 struct sk_buff *trailer;
343 struct crypto_ahash *ahash;
344 struct ahash_request *req;
345 struct scatterlist *sg;
346 struct ipv6hdr *top_iph;
347 struct ip_auth_hdr *ah;
349 struct tmp_ext *iph_ext;
354 if ((err = skb_cow_data(skb, 0, &trailer)) < 0)
358 skb_push(skb, -skb_network_offset(skb));
359 extlen = skb_network_header_len(skb) - sizeof(struct ipv6hdr);
361 extlen += sizeof(*iph_ext);
364 iph_base = ah_alloc_tmp(ahash, nfrags, IPV6HDR_BASELEN + extlen);
368 iph_ext = ah_tmp_ext(iph_base);
369 icv = ah_tmp_icv(ahash, iph_ext, extlen);
370 req = ah_tmp_req(ahash, icv);
371 sg = ah_req_sg(ahash, req);
373 ah = ip_auth_hdr(skb);
374 memset(ah->auth_data, 0, ahp->icv_trunc_len);
376 top_iph = ipv6_hdr(skb);
377 top_iph->payload_len = htons(skb->len - sizeof(*top_iph));
379 nexthdr = *skb_mac_header(skb);
380 *skb_mac_header(skb) = IPPROTO_AH;
382 /* When there are no extension headers, we only need to save the first
383 * 8 bytes of the base IP header.
385 memcpy(iph_base, top_iph, IPV6HDR_BASELEN);
388 #if defined(CONFIG_IPV6_MIP6) || defined(CONFIG_IPV6_MIP6_MODULE)
389 memcpy(iph_ext, &top_iph->saddr, extlen);
391 memcpy(iph_ext, &top_iph->daddr, extlen);
393 err = ipv6_clear_mutable_options(top_iph,
394 extlen - sizeof(*iph_ext) +
401 ah->nexthdr = nexthdr;
403 top_iph->priority = 0;
404 top_iph->flow_lbl[0] = 0;
405 top_iph->flow_lbl[1] = 0;
406 top_iph->flow_lbl[2] = 0;
407 top_iph->hop_limit = 0;
409 ah->hdrlen = (XFRM_ALIGN8(sizeof(*ah) + ahp->icv_trunc_len) >> 2) - 2;
413 ah->seq_no = htonl(XFRM_SKB_CB(skb)->seq.output.low);
415 sg_init_table(sg, nfrags);
416 skb_to_sgvec(skb, sg, 0, skb->len);
418 ahash_request_set_crypt(req, sg, icv, skb->len);
419 ahash_request_set_callback(req, 0, ah6_output_done, skb);
421 AH_SKB_CB(skb)->tmp = iph_base;
423 err = crypto_ahash_digest(req);
425 if (err == -EINPROGRESS)
433 memcpy(ah->auth_data, icv, ahp->icv_trunc_len);
434 memcpy(top_iph, iph_base, IPV6HDR_BASELEN);
437 #if defined(CONFIG_IPV6_MIP6) || defined(CONFIG_IPV6_MIP6_MODULE)
438 memcpy(&top_iph->saddr, iph_ext, extlen);
440 memcpy(&top_iph->daddr, iph_ext, extlen);
450 static void ah6_input_done(struct crypto_async_request *base, int err)
455 struct sk_buff *skb = base->data;
456 struct xfrm_state *x = xfrm_input_state(skb);
457 struct ah_data *ahp = x->data;
458 struct ip_auth_hdr *ah = ip_auth_hdr(skb);
459 int hdr_len = skb_network_header_len(skb);
460 int ah_hlen = (ah->hdrlen + 2) << 2;
462 work_iph = AH_SKB_CB(skb)->tmp;
463 auth_data = ah_tmp_auth(work_iph, hdr_len);
464 icv = ah_tmp_icv(ahp->ahash, auth_data, ahp->icv_trunc_len);
466 err = memcmp(icv, auth_data, ahp->icv_trunc_len) ? -EBADMSG: 0;
472 skb->network_header += ah_hlen;
473 memcpy(skb_network_header(skb), work_iph, hdr_len);
474 __skb_pull(skb, ah_hlen + hdr_len);
475 skb_set_transport_header(skb, -hdr_len);
477 kfree(AH_SKB_CB(skb)->tmp);
478 xfrm_input_resume(skb, err);
483 static int ah6_input(struct xfrm_state *x, struct sk_buff *skb)
487 * [IPv6][Ext1][Ext2][AH][Dest][Payload]
488 * |<-------------->| hdr_len
491 * Keeping copy of cleared headers. After AH processing,
492 * Moving the pointer of skb->network_header by using skb_pull as long
493 * as AH header length. Then copy back the copy as long as hdr_len
494 * If destination header following AH exists, copy it into after [Ext2].
496 * |<>|[IPv6][Ext1][Ext2][Dest][Payload]
497 * There is offset of AH before IPv6 header after the process.
503 struct sk_buff *trailer;
504 struct crypto_ahash *ahash;
505 struct ahash_request *req;
506 struct scatterlist *sg;
507 struct ip_auth_hdr *ah;
508 struct ipv6hdr *ip6h;
516 if (!pskb_may_pull(skb, sizeof(struct ip_auth_hdr)))
519 /* We are going to _remove_ AH header to keep sockets happy,
520 * so... Later this can change. */
521 if (skb_cloned(skb) &&
522 pskb_expand_head(skb, 0, 0, GFP_ATOMIC))
525 skb->ip_summed = CHECKSUM_NONE;
527 hdr_len = skb_network_header_len(skb);
528 ah = (struct ip_auth_hdr *)skb->data;
532 nexthdr = ah->nexthdr;
533 ah_hlen = (ah->hdrlen + 2) << 2;
535 if (ah_hlen != XFRM_ALIGN8(sizeof(*ah) + ahp->icv_full_len) &&
536 ah_hlen != XFRM_ALIGN8(sizeof(*ah) + ahp->icv_trunc_len))
539 if (!pskb_may_pull(skb, ah_hlen))
543 if ((err = skb_cow_data(skb, 0, &trailer)) < 0)
547 ah = (struct ip_auth_hdr *)skb->data;
548 ip6h = ipv6_hdr(skb);
550 skb_push(skb, hdr_len);
552 work_iph = ah_alloc_tmp(ahash, nfrags, hdr_len + ahp->icv_trunc_len);
556 auth_data = ah_tmp_auth(work_iph, hdr_len);
557 icv = ah_tmp_icv(ahash, auth_data, ahp->icv_trunc_len);
558 req = ah_tmp_req(ahash, icv);
559 sg = ah_req_sg(ahash, req);
561 memcpy(work_iph, ip6h, hdr_len);
562 memcpy(auth_data, ah->auth_data, ahp->icv_trunc_len);
563 memset(ah->auth_data, 0, ahp->icv_trunc_len);
565 if (ipv6_clear_mutable_options(ip6h, hdr_len, XFRM_POLICY_IN))
569 ip6h->flow_lbl[0] = 0;
570 ip6h->flow_lbl[1] = 0;
571 ip6h->flow_lbl[2] = 0;
574 sg_init_table(sg, nfrags);
575 skb_to_sgvec(skb, sg, 0, skb->len);
577 ahash_request_set_crypt(req, sg, icv, skb->len);
578 ahash_request_set_callback(req, 0, ah6_input_done, skb);
580 AH_SKB_CB(skb)->tmp = work_iph;
582 err = crypto_ahash_digest(req);
584 if (err == -EINPROGRESS)
590 err = memcmp(icv, auth_data, ahp->icv_trunc_len) ? -EBADMSG: 0;
594 skb->network_header += ah_hlen;
595 memcpy(skb_network_header(skb), work_iph, hdr_len);
596 skb->transport_header = skb->network_header;
597 __skb_pull(skb, ah_hlen + hdr_len);
607 static void ah6_err(struct sk_buff *skb, struct inet6_skb_parm *opt,
608 u8 type, u8 code, int offset, __be32 info)
610 struct net *net = dev_net(skb->dev);
611 struct ipv6hdr *iph = (struct ipv6hdr*)skb->data;
612 struct ip_auth_hdr *ah = (struct ip_auth_hdr*)(skb->data+offset);
613 struct xfrm_state *x;
615 if (type != ICMPV6_DEST_UNREACH &&
616 type != ICMPV6_PKT_TOOBIG)
619 x = xfrm_state_lookup(net, skb->mark, (xfrm_address_t *)&iph->daddr, ah->spi, IPPROTO_AH, AF_INET6);
623 NETDEBUG(KERN_DEBUG "pmtu discovery on SA AH/%08x/%pI6\n",
624 ntohl(ah->spi), &iph->daddr);
625 ip6_update_pmtu(skb, net, info, 0, 0);
629 static int ah6_init_state(struct xfrm_state *x)
631 struct ah_data *ahp = NULL;
632 struct xfrm_algo_desc *aalg_desc;
633 struct crypto_ahash *ahash;
641 ahp = kzalloc(sizeof(*ahp), GFP_KERNEL);
645 ahash = crypto_alloc_ahash(x->aalg->alg_name, 0, 0);
650 if (crypto_ahash_setkey(ahash, x->aalg->alg_key,
651 (x->aalg->alg_key_len + 7) / 8))
655 * Lookup the algorithm description maintained by xfrm_algo,
656 * verify crypto transform properties, and store information
657 * we need for AH processing. This lookup cannot fail here
658 * after a successful crypto_alloc_hash().
660 aalg_desc = xfrm_aalg_get_byname(x->aalg->alg_name, 0);
663 if (aalg_desc->uinfo.auth.icv_fullbits/8 !=
664 crypto_ahash_digestsize(ahash)) {
665 pr_info("AH: %s digestsize %u != %hu\n",
666 x->aalg->alg_name, crypto_ahash_digestsize(ahash),
667 aalg_desc->uinfo.auth.icv_fullbits/8);
671 ahp->icv_full_len = aalg_desc->uinfo.auth.icv_fullbits/8;
672 ahp->icv_trunc_len = x->aalg->alg_trunc_len/8;
674 BUG_ON(ahp->icv_trunc_len > MAX_AH_AUTH_LEN);
676 x->props.header_len = XFRM_ALIGN8(sizeof(struct ip_auth_hdr) +
678 switch (x->props.mode) {
680 case XFRM_MODE_TRANSPORT:
682 case XFRM_MODE_TUNNEL:
683 x->props.header_len += sizeof(struct ipv6hdr);
694 crypto_free_ahash(ahp->ahash);
700 static void ah6_destroy(struct xfrm_state *x)
702 struct ah_data *ahp = x->data;
707 crypto_free_ahash(ahp->ahash);
711 static const struct xfrm_type ah6_type =
713 .description = "AH6",
714 .owner = THIS_MODULE,
716 .flags = XFRM_TYPE_REPLAY_PROT,
717 .init_state = ah6_init_state,
718 .destructor = ah6_destroy,
720 .output = ah6_output,
721 .hdr_offset = xfrm6_find_1stfragopt,
724 static const struct inet6_protocol ah6_protocol = {
725 .handler = xfrm6_rcv,
726 .err_handler = ah6_err,
727 .flags = INET6_PROTO_NOPOLICY,
730 static int __init ah6_init(void)
732 if (xfrm_register_type(&ah6_type, AF_INET6) < 0) {
733 pr_info("%s: can't add xfrm type\n", __func__);
737 if (inet6_add_protocol(&ah6_protocol, IPPROTO_AH) < 0) {
738 pr_info("%s: can't add protocol\n", __func__);
739 xfrm_unregister_type(&ah6_type, AF_INET6);
746 static void __exit ah6_fini(void)
748 if (inet6_del_protocol(&ah6_protocol, IPPROTO_AH) < 0)
749 pr_info("%s: can't remove protocol\n", __func__);
751 if (xfrm_unregister_type(&ah6_type, AF_INET6) < 0)
752 pr_info("%s: can't remove xfrm type\n", __func__);
756 module_init(ah6_init);
757 module_exit(ah6_fini);
759 MODULE_LICENSE("GPL");
760 MODULE_ALIAS_XFRM_TYPE(AF_INET6, XFRM_PROTO_AH);